Joan Hartigveldt, b. 1616 or 1617 at Rotterdam, Netherlands, d. there 22 October 1678, was descended from a Reformed patrician family, studied law at the University of Leiden, entered a diplomatic career at London and Paris, and was converted shortly after 1645. He then abandoned all posts of honor and retired to a farm near Bridle, province of South Holland, henceforth living soberly and wearing plain black clothes. He gave serious consideration to joining a Christian church, but both the Reformed and the Remonstrants seemed to him to have forsaken the Christian simplicity of life and church ceremonies found among the earliest followers of Christ. He laid much stress upon the claim that in the meeting of Christians everyone was competent to preach the Gospel, not only the ministers appointed to this end. He rejected baptism as an obsolete ceremony. About 1650 he joined the Rijnsburg Collegiants and soon became an influential member of the "college" at Rotterdam, which was also attended by a large number of Mennonites, both of the Flemish and the Waterlander congregations. These Mennonites, influenced by Hartigveldt, tried to introduce his ideas in the congregations (free speaking, open communion, baptism by immersion and even joining without baptism). This caused trouble in the Flemish congregation (in 1652) as well as in the Waterlander congregation of Rotterdam (in 1661 and 1672-1673). Anonymously Hartigveldt wrote a book, in which he tried to promote a union between the Remonstrants and the Mennonites: Schriftuerlijke waardeeringe van het hedendaaghse Predicken en Kerckgaan, . . . (Rotterdam, 1672). He was a man of noble character and rejected government offices, repudiated war, and championed an absolute nonresistance. He was very charitable; he gave away nearly his entire fortune, left to him by his mother, and willed his remaining property to the Collegiant orphanage.